@sad0708
a) f(x) + g(x) = ( $x^{2}$ + 3x - 5 ) + ( $x^{2}$ + 2x + 3 )
= $x^{2}$ + 3x - 5 + $x^{2}$ + 2x + 3
= ( $x^{2}$ + $x^{2}$ ) + ( 3x + 2x ) + ( -5 + 3 )
= $2x^{2}$ + 5x + -2
b) f(x) - g(x) = ( $x^{2}$ + 3x - 5 ) - ( $x^{2}$ + 2x + 3 )
= $x^{2}$ + 3x - 5 - $x^{2}$ - 2x - 3
= ( $x^{2}$ - $x^{2}$ ) + ( 3x - 2x ) + ( -5 - 3 )
= x + -8